Effect of N-acetyl cysteine, rifampicin, and ozone on biofilm formation in pan-resistant<i> Klebsiella</i><i> pneumoniae:</i> an experimental study

BACKGROUND: To the best of our knowledge, this is the first study to evaluate the effectiveness of specific concentrations of antibiofilm agents, such as N -acetyl cysteine (NAC), rifampicin, and ozone, for the treatment of pan -resistant Klebsiella pneumoniae (PRKp). OBJECTIVES: We evaluated the effectiveness of antibiofilm agents, such as NAC, rifampicin, and ozone, on biofilm formation in PRKp at 2, 6, 24, and 72 h. DESIGN AND SETTING: This single -center experimental study was conducted on June 15, 2017, and July 15, 2018, at Istanbul Faculty of Medicine, Istanbul University, Turkey. METHODS: Biofilm formation and the efficacy of these agents on the biofilm layer were demonstrated using colony counting and laser -screened confocal microscopy. RESULTS: NAC at a final concentration of 2 mu g/mL was administered to bacteria that formed biofilms (24 h), and no significant decrease was detected in the bacterial counts of all isolates (all P > 0.05). Rifampicin with a final concentration of 0.1 mu g/mL was administered to bacteria that formed biofilm (24 h), and no significant decrease was detected in bacterial count (all P > 0.05). Notably, ozonated water of even 4.78 mg/L concentration for 72 h decreased the bacterial count by >= 2 log10. CONCLUSION: Different approaches are needed for treating PRKp isolates. We demonstrate that PRKp isolates can be successfully treated with higher concentrations of ozone.